1,167 research outputs found
Combining Information from Two Surveys to Estimate County-Level Prevalence Rates of Cancer Risk Factors and Screening
Cancer surveillance requires estimates of the prevalence of cancer risk factors and screening for small areas such as counties. Two popular data sources are the Behavioral Risk Factor Surveillance System (BRFSS), a telephone survey conducted by state agencies, and the National Health Interview Survey (NHIS), an area probability sample survey conducted through face-to-face interviews. Both data sources have advantages and disadvantages. The BRFSS is a larger survey, and almost every county is included in the survey; but it has lower response rates as is typical with telephone surveys, and it does not include subjects who live in households with no telephones. On the other hand, the NHIS is a smaller survey, with the majority of counties not included; but it includes both telephone and non-telephone households and has higher response rates. A preliminary analysis shows that the distributions of cancer screening and risk factors are different for telephone and non-telephone households. Thus, information from the two surveys may be combined to address both nonresponse and noncoverage errors. A hierarchical Bayesian approach that combines information from both surveys is used to construct county-level estimates. The proposed model incorporates potential noncoverage and nonresponse biases in the BRFSS as well as complex sample design features of both surveys. A Markov Chain Monte Carlo method is used to simulate draws from the joint posterior distribution of unknown quantities in the model based on the design-based direct estimates and county-level covariates. Yearly prevalence estimates at the county level for 49 states, as well as for the entire state of Alaska and the District of Columbia, are developed for six outcomes using BRFSS and NHIS data from the years 1997-2000. The outcomes include smoking and use of common cancer screening procedures. The NHIS/BRFSS combined county-level estimates are substantially different from those based on BRFSS alone
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Exploring pulse shaping for Z using graded-density impactors on gas guns (final report for LDRD project 79879).
While isentropic compression experiment (ICE) techniques have proved useful in deducing the high-pressure compressibility of a wide range of materials, they have encountered difficulties where large-volume phase transitions exist. The present study sought to apply graded-density impactor methods for producing isentropic loading to planar impact experiments to selected such problems. Cerium was chosen due to its 20% compression between 0.7 and 1.0 GPa. A model was constructed based on limited earlier dynamic data, and applied to the design of a suite of experiments. A capability for handling this material was installed. Two experiments were executed using shock/reload techniques with available samples, loading initially to near the gamma-alpha transition, then reloading. As well, two graded-density impactor experiments were conducted with alumina. A method for interpreting ICE data was developed and validated; this uses a wavelet construction for the ramp wave and includes corrections for the ''diffraction'' of wavelets by releases or reloads reflected from the sample/window interface. Alternate methods for constructing graded-density impactors are discussed
Modulational instability of bright solitary waves in incoherently coupled nonlinear Schr\"odinger equations
We present a detailed analysis of the modulational instability (MI) of
ground-state bright solitary solutions of two incoherently coupled nonlinear
Schr\"odinger equations. Varying the relative strength of cross-phase and
self-phase effects we show existence and origin of four branches of MI of the
two-wave solitary solutions. We give a physical interpretation of our results
in terms of the group velocity dispersion (GVD) induced polarization dynamics
of spatial solitary waves. In particular, we show that in media with normal GVD
spatial symmetry breaking changes to polarization symmetry breaking when the
relative strength of the cross-phase modulation exceeds a certain threshold
value. The analytical and numerical stability analyses are fully supported by
an extensive series of numerical simulations of the full model.Comment: Physical Review E, July, 199
NuSTAR observatory science operations: on-orbit acclimation
The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing high energy (3-79 keV) X-ray observatory. The NuSTAR project is led by Caltech, which hosts the Science Operations Center (SOC), with mission operations managed by UCB Space Sciences Laboratory. We present an overview of NuSTAR science operations and describe the on-orbit performance of the observatory. The SOC is enhancing science operations to serve the community with a guest observing program beginning in 2015. We present some of the challenges and approaches taken by the SOC to operating a full service space observatory that maximizes the scientific return from the mission
Changes in symptom clusters in patients undergoing radiation therapy
The goals of the study were to determine the occurrence rates for and the severity of symptoms at the middle, end, and 1Â month after the completion of radiation therapy (RT), to determine the number and types of symptom clusters at these three time points, and to evaluate for changes over time in these symptom clusters.
Symptom occurrence and severity were evaluated using the Memorial Symptom Assessment Scale (MSAS) in a sample of patients (n = 160) who underwent RT for breast or prostate cancer. At each time point, an exploratory factor analysis was done to determine the number of symptom clusters (i.e., symptom factors) based on the MSAS symptom severity ratings.
The majority of the patients were male and married with a mean age of 61.1 years. The five symptoms with the highest occurrence rates across all three time points were lack of energy, pain, difficulty sleeping, feeling drowsy, and sweats. Although the number of symptoms and the specific symptoms within each symptom cluster were not identical across the three time points, three relatively similar symptom clusters (i.e., “mood-cognitive” symptom cluster, “sickness-behavior” symptom cluster, “treatment-related”, or “pain” symptom cluster) were identified in this sample. The internal consistency coefficients for the mood-cognitive symptom cluster and sickness-behavior symptom cluster were adequate at ≥0.68.
Three relatively stable symptom clusters were found across RT. The majority of the symptom cluster severity scores were significantly higher in patients with breast cancer compared to patients with prostate cancer
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